Generate a pending list from multiple sheets

Hi there,

I'm really stuck with what I'm trying to do and I'm not even sure if it's possible.

In my line of work I send off samples to other labs for testing. These are logged onto a spreadsheet and the empty fields are filled once results are received. In my example spreadsheet, Column N is blank whenever a result has yet to be received and should therefore appear on the newly generated pending list sheet. I can get a list generated from one sheet but not multiple sheets.

If this can be done then great! But it would be ideal if I could take this one step further. The example spreadsheet given would be for 2014. Would it be possible to have the previous year's workbook (2013) scanned also for pending requests and added to the 'Pending' sheet list? This list should ideally be displayed in date order with the oldest pending request first.

Any help would be much appreciated,

Steven